@Paul *******
My thoughts as well. What I think Thai immigration would do in such cases would be to require in country extensions every 6 months since the borders would be closed. They'd then be able to require all sorts of documentation, which is as yet unknown.
Having said that, should this happen again, I think they'd probably have an amnesty for the first few months, meaning you'd receive an automatic extension of stay during those times.
Let's hope they never do another lockdown/border closure again. If they do, some indications are it might happen end of 2025 or 2026 but this is mere speculation based on certain clues being put out at this point.